Editing Composting toilet (section)

=== Additives and bulking material ===
Human waste and food waste do not provide optimum conditions for composting. Usually the water and nitrogen content is too high, particularly when urine is mixed with feces. Additives or "bulking material", such as wood chips, bark chips, sawdust, shredded dry leaves, ash and pieces of paper can absorb moisture. The additives improve pile aeration and increase the carbon to nitrogen ratio.<ref name=":1" /> Bulking material also covers feces and reduces insect access. Absent sufficient bulking material, the material may become too compact and form impermeable layers, which leads to anaerobic conditions and odour.<ref name=":1" />